Use of a grommet 101 shown in FIG. 9 (for example, see Patent Literature 1) is common when a wiring harness is passed through a hole in a panel of a body of a vehicle, which may be an automobile, in a case where a liquid such as water should be prevented from coming into contact with the wiring harness.
The grommet 101 of FIG. 9 may be made of a rubber and include in one piece therewith a cylindrical portion 105; a body 102 continuous to the cylindrical portion 105, with an inner diameter and an outer diameter thereof gradually increased from one end thereof to an other end thereof; a second cylindrical portion 106 continuing to the other end of the body 102; a locking recess 103 provided along an entire periphery of the body 102 and configured to be locked into the hole in the panel; and a lip 104 operable to adhere to the panel.
When mounting the grommet 101 into the hole in the panel, an operator may insert the grommet 101 from the side of the cylindrical portion 105 into the hole in the panel along its central axis P; press a proximal portion of the body 102 (which is defined to be proximal with reference to the central axis P) toward the distal side (which is defined to be distal with reference to the central axis P); grasp the cylindrical portion 105 and/or the second cylindrical portion 106 to pull the body 102 to the proximal side; alternately and repeatedly apply upon the proximal portion (a) a pressing force acting from the proximal side to the distal side and (b) a pressing force acting from the distal side to the proximal side; thereby cause the body 102 to elastically deform in a diameter-contracting direction (here, “diameter-contracting” refers to decreasing of the inner and outer diameters); and locks the locking recess 103 in the hole, so that the grommet 101 is attached to the panel.    [Patent Literature] Japanese Patent Application Laid-Open Publication No. H07-163034